When comparing TestingBot vs BugBug.io, the Slant community recommends BugBug.io for most people. In the question“What are the best cloud-based cross-browser testing services?” BugBug.io is ranked 8th while TestingBot is ranked 11th. The most important reason people chose BugBug.io is:
You are able to group the steps in tests into reusable components to manage and repair them easier. As a bonus, you can see all test flows on a single project graph.
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Runs Selenium tests

Pro Appium support

Pro Secure tunnel for testing code locally

Pro Run tests in parallel

Pro Allows testing both manually and automatically in several browsers and platforms
You can test your website both manually and automatically with TestingBot in different browsers and platforms.
Pro Pristine VM for each test
TestingBot guarantees a fresh, untouched virtual machine for every test, unlike with browserstack
Pro Free for 100 minutes
Free accounts receive 100 minutes free manual testing, paid accounts have unlimited manual testing minutes.
Pro Latest browsers (beta/dev)
You can run tests on the beta/dev builds of browsers, to make sure everything works on upcoming browser version releases.

Pro Real mobile devices
TestingBot now offers Real Mobile Devices in its datacenter, capable of running both automated and manual tests.

Pro Manual testing
Pro Reusable components
You are able to group the steps in tests into reusable components to manage and repair them easier. As a bonus, you can see all test flows on a single project graph.
Pro Great UI & UX
A design for a high efficiency
Pro Debuggability
You can run tests and debug directly from a Chrome browser, where you have access to DevTools.
Cons

Con Uses mobile emulators instead of real devices
Unlike CrossBrowserTesting, TestingBot uses mobile emulators.
